This seems like it was implemented intentionally but in practice seems like a very huge oversight.

I'm in legend league and constantly tweak my base to thwart the evolving attack styles. If I make a change to my base, I cannot make it the active base for 24 hours from the last change made (base is locked from selection), and then it won't become active until the next league day, which means I'll have to continue using the current base for at least the remainder of the current league day PLUS one full league day.

If I notice a wall is out of place, or accidentally move a piece while trying to zoom in or out, I now have to wait 1+ league day to see any changes take affect.

Likewise, if I'm trying to test revisions to a base, thanks to a combination of the cool down to implement a base change in legend league, and the cooldown to issue a friendly base challenge, my only viable option to tune the base under constant attack is to completely drop out of legend league into Titan I, test the base changes by making it available to attack, and then climbing back up into Legend League.

This is tedious and non-sensical. Take away the 24-hour cooldown to make base revisions live in legend league. It's cool for the snapshot to not take affect until the next League Day but to not even allow us to select it until 24 hours has gone by is beyond ridiculous.